JP5473561B2 - Glass-ceramic wiring board, glass-ceramic wiring board with built-in coil, and method for manufacturing glass-ceramic wiring board - Google Patents

Description

  The present invention relates to a glass ceramic wiring board in which a ferrite layer and an insulating layer are laminated to form a wiring conductor on the surface and inside, and a coil having a built-in coil in the ferrite layer and a wiring conductor formed in the insulating layer The present invention relates to a glass ceramic wiring board and a method for manufacturing a glass ceramic wiring board.

  Conventionally, a large number of electronic devices have been incorporated in electronic devices such as mobile communication devices such as mobile phones, and various electronic devices have become smaller as electronic devices have become increasingly smaller. There is a demand for downsizing, thinning and high density. For example, an LC filter is conventionally formed by mounting a relatively large chip coil or chip capacitor on a substrate, but in recent years, a ferrite layer having a high magnetic permeability is formed inside a ceramic substrate. It has been proposed to embed a coil conductor in a ferrite layer (see, for example, Patent Documents 1 and 2).

  Such a ceramic wiring board is constituted by, for example, a pair of insulating layers formed with a wiring layer and a ferrite layer sandwiched and laminated between the pair of insulating layers and having a coil conductor embedded therein. Yes. In order to suppress electrical loss due to resistance, it is necessary to use a low resistance metal such as Cu or Ag having low resistance, and such a low resistance metal has a relatively low melting point. A glass ceramic substrate is manufactured by simultaneously firing glass ceramic and ferrite as an insulating layer and a ferrite layer that can be fired at a low temperature, respectively.

  In addition, with recent downsizing and higher density of electronic devices, glass ceramic substrates have also been downsized, and it is necessary to mount electronic components accurately and at high density on such small glass ceramic substrates. It has become. And the glass ceramic wiring board which formed the wiring conductor by which the gold plating layer was adhere | attached on the surface of the above small glass ceramic substrates is used conventionally. However, since the glass ceramic wiring board is white and the gold plating layer deposited on the wiring conductor is a color close to white, the semiconductor is based on the wiring conductor using an automatic machine that mounts electronic components by image recognition. When an electronic component such as an element is to be mounted on a glass-ceramic wiring board, it is difficult to accurately recognize the wiring conductor image, so that there is a problem that it is difficult to position the electronic component. In addition, there is a problem that it is difficult to accurately connect each electrode of an electronic component to a predetermined wiring conductor when trying to wire-bond and connect each electrode of the electronic component such as a semiconductor element and the wiring conductor. It was.

  In order to solve these problems, a method has been proposed in which a color pigment is added to a glass ceramic wiring board to color the glass ceramic wiring board to facilitate image recognition. (For example, see Patent Document 3). As the color pigment, for example, a transition metal alone or an oxide can be used, and a glass ceramic wiring board of a desired color can be manufactured by mixing such a color pigment into glass ceramics.

JP-A-6-20839 JP-A-6-21264 JP 2001-97786 A

  However, the glass ceramic wiring board colored by adding a color pigment to glass ceramics has more voids in the insulating layer than the conventional glass ceramic wiring board to which no coloring pigment is added. And these voids are connected, the moisture that has penetrated through the connected multiple voids reaches the internal wiring, ion migration occurs between the internal wirings, and the internal wirings are short-circuited As a result, an electrical insulation failure may be caused, which causes a problem that insulation reliability is lowered and strength is lowered. This is because the crystal structure of the crystal and ferrite crystal in the glass ceramic is different from the crystal structure of the transition metal element or oxide crystal added as a color pigment. Because the constants are different, when the glass-ceramic wiring board is fired to crystallize the crystal and ferrite crystal in the glass ceramic, there is a gap between the crystallized portion and the transition metal simple substance or oxide crystal. It is considered that this gap is increased as firing proceeds, and voids are generated between the crystal or ferrite crystal in the glass ceramic and the transition metal element or oxide crystal.

  The present invention has been devised in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a glass-ceramic wiring board colored with an insulating layer, which can maintain the board strength and insulation reliability, and the glass. An object is to provide a glass-ceramic wiring board with a built-in coil using a ceramic wiring board.

The glass-ceramic wiring board of the present invention comprises a glass ceramic having a glass containing a glass phase and a first crystal, and a plurality of insulating layers containing a spinel second crystal made of a transition metal oxide or sulfide as a color pigment. And a plurality of ferrite layers provided between the plurality of insulating layers having a ferrite crystal, and a wiring conductor formed on the surface and inside thereof, the first crystal, the second crystal, and the ferrite crystal And the first crystal, the second crystal and the ferrite crystal have different lattice constants, and the difference in lattice constant between the first crystal and the second crystal is the second crystal. The lattice constant of the second crystal and the ferrite crystal is within 13.3% and the difference in lattice constant of the second crystal is within 11.4% of the lattice constant of the second crystal. A.

In the glass ceramic wiring board with a built-in coil according to the present invention, the first crystal is Mg ₂ SiO ₄ , the ferrite crystal is FeFe ₂ O ₄ , and the second crystal is FeV ₂ O _4. , CoCr ₂ O ₄ , MnCo ₂ O _4, and CoFe ₂ O ₄ .

  The glass-ceramic wiring board with a built-in coil according to the present invention is characterized in that a coil conductor is formed between the plurality of ferrite layers of the glass-ceramic wiring board having the above configuration.

The method for producing a glass-ceramic wiring board according to the present invention comprises a glass ceramic having a glass containing a glass phase and a first crystal, and a plurality of spinel-structure second crystals made of transition metal oxides or sulfides. An insulating layer, a plurality of ferrite layers having a ferrite crystal, and a plurality of ferrite layers provided between the plurality of insulating layers, and a wiring conductor formed on the surface and inside, the first crystal and the second crystal, The ferrite crystal has the same crystal structure, and the first crystal, the second crystal, and the ferrite crystal have different lattice constants, and the difference in lattice constant between the first crystal and the second crystal is together is within 13.3% of the lattice constant of the second crystal, the difference in lattice constant between the second crystal and the ferrite crystal is within 11.4% of the lattice constant of the second crystal Garasusera A click wiring board manufacturing method of a 10 to 40 wt% of a filler consisting of forsterite, the SiO ₂ from 22 to 52 _wt%, B 2 _{O 3} 2-12 wt%, the _Al 2 _{O 3} 9 to 29 wt%, the ZnO 9 to 29 wt%, including 7-21 wt% 1-9 wt% and MgO and CaO, and the molar ratio of the ZnO with respect to the _Al 2 _{O 3} is 0.8 to 1.2 60 A plurality of ceramic green sheets comprising 90% by mass of glass and 2-8% by mass of the coloring pigment made of any one of FeV ₂ O ₄ , CoCr ₂ O ₄ , MnCo ₂ O ₄ and CoFe ₂ O ₄ a first preparation step of preparing a second preparation step of preparing a ferrite green sheet having a FeFe ₂ O _4, the said ceramic green sheets and the ferrite green sheet, a conductor pattern serving as a wiring conductor layers A laminate manufacturing step of manufacturing a green sheet laminate by laminating to form the emission, is characterized in that it comprises a firing step of firing the green sheet laminate.

According to the glass ceramic wiring board of the present invention, the insulating layer contains the second crystal having the spinel structure made of the transition metal oxide or sulfide as the color pigment, and the first crystal, the second crystal, and the ferrite crystal are In the same crystal structure , the first crystal, the second crystal, and the ferrite crystal have different lattice constants, and the difference in lattice constant between the first crystal and the second crystal is 13.3 of the lattice constant of the second crystal. And the difference in lattice constant between the second crystal and the ferrite crystal is within 11.4% of the lattice constant of the second crystal, so that the crystal structure is the same and the crystal size is the same. Since generation of voids at the interface between the first crystal and the second crystal and the interface between the second crystal and the ferrite crystal can be reduced, a glass ceramic wiring board having a colored insulating layer while maintaining the substrate strength and insulation reliability; To do Kill. If such a glass ceramic wiring board is used, electronic components can be accurately and densely mounted on the wiring board.

According to the glass ceramic wiring board of the present invention, in the above configuration, the first crystal is Mg ₂ SiO ₄ , the ferrite crystal is FeFe ₂ O ₄ , and the second crystal is FeV ₂ O ₄ , CoCr _2. When any one of O ₄ , MnCo ₂ O _4, and CoFe ₂ O ₄ , the first crystal, the second crystal, and the ferrite crystal have the same crystal structure, and the first crystal and the second crystal The difference in lattice constant is within 3.7% of the lattice constant of the second crystal, the difference in lattice constant between the second crystal and the ferrite crystal is within 1.6% of the lattice constant of the second crystal, and the difference in lattice constant is Since it becomes smaller and voids are less generated, a glass ceramic wiring board with higher bonding strength can be obtained.

  In the glass-ceramic wiring board with a built-in coil according to the present invention, since the coil conductor is formed between the plurality of ferrite layers of the glass-ceramic wiring board having the above configuration, the coil conductor is formed in the ferrite layer having a high magnetic permeability. Therefore, it becomes a glass-ceramic wiring board with a built-in coil with high inductance.

According to the method for producing a glass-ceramic wiring board of the present invention, 10 to 40% by mass filler made of forsterite, 22 to 52% by mass of SiO ₂ , ₂ to 12% by mass of B ₂ O ₃ , Al ₂ O ₃ to 9 to 29% by mass, ZnO to 9 to 29% by mass, CaO to 1 to 9% by mass and MgO to 7 to 21% by mass, and the molar ratio of ZnO to Al ₂ O ₃ is 0.8 to 1.2 A plurality of ceramics having a glass of 60 to 90% by mass and ₂ to 8% by mass of a color pigment made of any one of FeV ₂ O ₄ , CoCr ₂ O ₄ , MnCo ₂ O ₄ and CoFe ₂ O ₄ a first preparation step of preparing a green sheet, a second preparation step of preparing a ferrite green sheet having a FeFe ₂ O _4, and the ceramic green sheets and the ferrite green sheets, wire guide in the interlayer Forming a conductor pattern and forming a green sheet laminate, and a firing step of firing the green sheet laminate, the first crystal and the second crystal A glass-ceramic wiring board with high substrate strength and high insulation reliability can be easily produced by a normal laminate production process and firing process without generating voids at the interface.

It is sectional drawing which shows an example of embodiment of the glass-ceramic wiring board of this invention. It is a fragmentary sectional view which shows an example of embodiment of the glass-ceramic wiring board with a built-in coil of this invention. It is sectional drawing in the AA of the glass-ceramic wiring board with a built-in coil shown in FIG.

  The example of embodiment of the glass ceramic wiring board of this invention is demonstrated in detail below, referring an accompanying drawing.

  1 to 3, 1 is an insulating layer, 2 is a ferrite layer, 3 is a wiring conductor, and 4 is a coil conductor.

  The glass ceramic wiring board of the present invention is made of glass ceramics having a glass containing a glass phase and a first crystal as shown in FIGS. 1 to 3, and a spinel structure made of an oxide or sulfide of a transition metal. A plurality of insulating layers 1 containing the second crystal as a color pigment, a plurality of ferrite layers 2 having ferrite crystals provided between the plurality of insulating layers 1, and a wiring conductor 3 formed on the surface and inside thereof. The first crystal, the second crystal and the ferrite crystal have the same crystal structure, and the difference in lattice constant between the first crystal and the second crystal is within 13.3% of the lattice constant of the second crystal. The difference in lattice constant between the second crystal and the ferrite crystal is within 11.4% of the lattice constant of the second crystal.

  According to such a glass-ceramic wiring board of the present invention, the insulating layer 1 includes the second crystal having a spinel structure made of an oxide or sulfide of a transition metal as a color pigment, and the first crystal, the second crystal, The ferrite crystal has the same crystal structure, and the difference in lattice constant between the first crystal and the second crystal is within 13.3% of the lattice constant of the second crystal, and the lattice constant between the second crystal and the ferrite crystal. Since the difference between the two is within 11.4% of the lattice constant of the second crystal, the generation of voids at the interface between the first crystal and the second crystal and the interface between the second crystal and the ferrite crystal can be reduced. While maintaining strength and insulation reliability, the insulating layer 1 can be colored glass ceramic wiring board. If such a glass ceramic wiring board is used, the wiring conductor 3 formed on the surface of the colored insulating layer 1 can be accurately recognized, so that electronic components can be mounted on the wiring board accurately and with high density. can do.

According to the glass ceramic wiring board of the present invention, in the above configuration, the first crystal is Mg ₂ SiO ₄ , the ferrite crystal is FeFe ₂ O ₄ , and the second crystal is FeV ₂ O ₄ , CoCr _2. When any one of O ₄ , MnCo ₂ O _4, and CoFe ₂ O ₄ , the first crystal, the second crystal, and the ferrite crystal have the same crystal structure, and the first crystal and the second crystal The difference in lattice constant is within 3.7% of the lattice constant of the second crystal, the difference in lattice constant between the second crystal and the ferrite crystal is within 1.6% of the lattice constant of the second crystal, and the difference in lattice constant is Since it becomes smaller and voids are less generated, a glass ceramic wiring board with higher bonding strength can be obtained.

  Further, in the glass-ceramic wiring board with a built-in coil according to the present invention, since the coil conductor is formed between the plurality of ferrite layers of the glass-ceramic wiring board according to the present invention having the above-described configuration, Thus, a glass ceramic wiring board with high inductance is obtained. As a result, in the case of having desired electrical characteristics and high insulation reliability, mounting a component on the wiring conductor 3 or mounting a glass ceramic wiring board on the external circuit board via the wiring conductor 3 A glass ceramic wiring board with high mounting reliability can be obtained.

In the example shown in FIG. 1, the ferrite layer 2 is a ferromagnetic ferrite that is a solid solution having a spinel structure, and is a Ni—Zn-based ferrite, Y—Fe represented as X—Fe ₂ O ₄ (X is Cu, Ni, or Zn). Mn—Zn based ferrite represented as ₂ O ₄ (Y is Mn or Zn), Mg—Zn based ferrite represented as Z—Fe ₂ O ₄ (Z is Mg or Zn) or U—Fe ₂ O ₄ (U is Ni-Co based ferrite shown as Ni or Co). Among these, FeFe ₂ O ₄ is a main component of the spinel structure. Among the ferromagnetic ferrites having the above spinel structure, Ni—Zn ferrite can obtain a sufficiently high magnetic permeability in a high frequency band, and thus is preferably used in applications using a high frequency of 10 MHz or more.

In the case of Ni—Zn ferrite, the composition ratio is 63 to 73 mass% of FeFe ₂ O ₄ as a sintered body, 5 to 10 mass% of CuO, 5 to 12 mass% of NiO, and 10 to 10 of ZnO. When the content is 23% by mass, high-density firing with a sintered density of 5 g / cm ³ or more is possible at a temperature of 800 to 1000 ° C. or less at which the glass ceramic of the insulating layer 1 is fired, and sufficiently high permeability in a high-frequency band. Is preferable. FeFe ₂ O ₄ is a main component of ferrite, and a sufficient magnetic permeability can be obtained when the ratio is 63% by mass or more. Further, when FeFe ₂ O ₄ is 73 mass% or less, it is possible to retain the mechanical strength without lowering the sintering density. CuO is an important factor for lowering the sintering temperature, and CuO promotes sintering by forming a liquid phase at a low temperature, and the low temperature of 800 to 1000 ° C. without damaging the magnetic properties. Can be fired. If the proportion of CuO is 5% by mass or more, the sintering density can be increased when fired at 800 to 1000 ° C. simultaneously with the wiring layer and the coil conductor, so that the mechanical strength can be maintained. In addition, when the content is 10% by mass or less, the ratio of CuFe ₂ O ₄ having a low magnetic property can be suppressed to be low, so that the magnetic property is easily maintained. NiO is contained in order to ensure the magnetic permeability of the ferrite layer 2 in the high frequency range. NiFe ₂ O ₄ does not cause the attenuation of the magnetic permeability due to resonance up to the high frequency range, and can maintain the magnetic permeability in the high frequency range at a relatively high value. If it is at least%, it is possible to maintain the magnetic permeability in a high frequency region of 10 MHz or more without lowering, and if it is at most 12% by mass, the initial permeability can be kept high. ZnO is an important element for improving the magnetic permeability of the ferrite layer 2. If the ferrite composition is 10% by mass or more, the magnetic permeability can be kept high. It can be maintained well.

The ferrite layer 2 is produced by firing a ferrite green sheet for the ferrite layer 2. The ferromagnetic ferrite powder used for the ferrite green sheet is a ferrite powder prepared by pre-calcining FeFe ₂ O ₄ and CuO, ZnO, or NiO, for example, and has an average particle size of 0.1 to 0.9 μm. It is preferable that the grain shape is close to a spherical shape. This is because when the average particle size is 0.1 μm or more, uniform dispersion of the ferrite powder is facilitated in the production of the ferrite green sheet, and when the average particle size is 0.9 μm or less, the sintering temperature of the ferrite green sheet is kept low. Because it can. Moreover, a uniform sintered state can be obtained because the particle diameter is uniform and nearly spherical. When the grain size of the ferrite powder is within the above range, the crystal grain growth does not decrease locally, and the permeability of the ferrite layer 2 obtained after sintering tends to be stable.

The insulating layer 1 is made of a glass ceramic having a glass containing a glass phase and a first crystal, and includes a spinel second crystal made of an oxide or sulfide of a transition metal as a color pigment. As the glass phase, SiO ₂ system, SiO ₂ —B ₂ O ₃ system, SiO ₂ —Al ₂ O ₃ system, SiO ₂ —MO system (where M represents Ca, Sr, Mg, Ba or Zn), SiO ₂ —B ₂ O ₃ system—MO system, SiO ₂ —M ¹ O—M ² O system (provided that M ¹ and M ² are the same or different and represent Ca, Sr, Mg, Ba or Zn), SiO _2- B ₂ O ₃ -M ¹ O-M ² O system, SiO ₂ -M ³ ₂ O system (where M ³ represents Li, Na or K) and SiO ₂ -B ₂ O ₃ -M ³ ₂ O-type glass etc. are mentioned. In addition to the above, Co, Cd, In and oxides thereof may be included.

The first crystal is obtained by firing a ceramic green sheet for the insulating layer 1 to crystallize the glass in the ceramic green sheet for the insulating layer 1 containing glass powder and filler powder, or a glass component. These are crystals generated from the filler component, crystals of the filler component, or crystals contained in the ceramic green sheet for the insulating layer 1. Examples of the glass that crystallizes into a spinel structure include SiO ₂ —Al ₂ O ₃ —MgO glass (provided that the molar ratio of MgO to Al ₂ O ₃ is 0.8 to 1.2), SiO ₂ —MgO glass (provided that SiO ₂ MgO to molar ratio of 1.8 to 2.2), SiO ₂ —Al ₂ O ₃ —ZnO glass (provided that the molar ratio of ZnO to Al ₂ O ₃ is 0.8 to 1.2), SiO ₂ —CoO—MnO ₂ glass (provided that The molar ratio of CoO to MnO ₂ is 1.8 to 2.2), and the SiO ₂ —CdO—InO ₂ glass (however, the molar ratio of CdO to InO _{2 is} 1.8 to 2.2). If MgO is included as the glass component and SiO ₂ is included as the filler component, Mg ₂ SiO ₄ is generated as the first crystal. Or if ZnO is contained as a glass component and Al ₂ O ₃ is contained as a filler component, ZnAl ₂ O ₄ is generated as a first crystal. Alternatively, if Al ₂ O ₃ is included as a glass component and Fe ₂ O ₃ is included as a filler component, FeAl ₂ O ₄ is generated. When the first crystal is contained in the ceramic green sheet as a filler, for example, forsterite (Mg ₂ SiO ₄ ) or garnite (ZnAl ₂ O ₄ ) can be mentioned.

The first crystal is not particularly limited as long as it has the same crystal structure as the ferrite crystal. For example, if the ferrite crystal has the spinel structure as described above, forsterite (Mg ₂ SiO ₄ ). And garnite (ZnAl ₂ O ₄ ).

The second crystal which is a color pigment is not particularly limited as long as it is a spinel crystal composed of an oxide or sulfide of a transition metal and has the same crystal structure as the first crystal and the ferrite crystal. For example, Ag ₂ MnO ₄ , CdCr ₂ O _4, CoCr ₂ O ₄ , CoFe ₂ O ₄ , Co ₂ MnO ₄ , Co ₂ TiO ₄ , CuFe ₂ O ₄ , CuCr ₂ O ₄ , CuMn ₂ O ₄ , CuCo ₂ S ₄ , FeV ₂ O ₄ , MgMn ₂ O ₄ or MnCo ₂ O ₄ may be mentioned.

  The second crystal, the first crystal, and the ferrite crystal have the same spinel type crystal structure, and the difference in lattice constant between the first crystal and the second crystal is within 13.3% of the lattice constant of the second crystal. The difference in lattice constant between the second crystal and the ferrite crystal is within 11.4% of the lattice constant of the second crystal. Thus, when the second crystal has the same crystal structure and the same size as the first crystal, the interface between the first crystal and the second crystal and the interface between the second crystal and the ferrite crystal are formed at the time of firing. Since the generation of gaps can be reduced, generation of voids can be reduced, and a glass-ceramic wiring board with a colored insulating layer can be obtained while maintaining the board strength and insulation reliability. If such a glass ceramic wiring board is used, the wiring conductor 3 formed on the surface of the colored insulating layer 1 can be accurately recognized, so that electronic components can be mounted on the wiring board accurately and with high density. can do.

Here, as a method of confirming the crystal structures of the first crystal, the second crystal, and the ferrite crystal in the insulating layer 1, there is a method using a transmission electron microscope. According to this method, the ceramic substrate is first cut and the cut surface is polished, and the layer whose crystal structure is to be confirmed, that is, either the insulating layer 1 or the ferrite layer 2 can be observed with a transmission electron microscope. Put it in a state. Thereafter, the crystal structure of the desired layer can be identified by observing the diffraction grating image at the cut surface of the layer. Identification of the crystal phase can be performed using a JPCDS card for known ones. For example, the crystal structure and diffraction grating image of ZnFe ₂ O ₄ , FeAl ₂ O ₄ or ZnAl ₂ O ₄ are JPCDS cards (ZnFe ₂ O ₄ : JPCDS No. 22-1012, FeAl ₂ O ₄ : JPCDS No. 34-0192). , ZnAl ₂ O ₄ : JPCDS No. 5-669), it can be easily confirmed whether or not the crystal phase is precipitated.

  As a method for confirming the crystal structures of the first crystal, the second crystal, and the ferrite crystal other than the method using the transmission electron microscope, there is a method using the X-ray diffraction method. According to this method, a desired layer can be observed by X-ray diffraction in the same manner as when a transmission electron microscope is used. Thereafter, a diffraction grating image can be obtained by irradiating the cross section of the layer with X-rays. The X-ray irradiation is performed on an area of about 10 μm square so that only a desired layer portion is irradiated. Thereafter, the crystal structure of the first crystal, the second crystal, and the ferrite layer 2 can be specified by the same procedure as the identification of the crystal structure by the transmission electron microscope.

  Such a glass ceramic wiring board of the present invention includes a first preparation step of preparing a ceramic green sheet for the insulating layer 1, a second preparation step of preparing a ferrite green sheet for the ferrite layer 2, a ceramic green sheet, It is produced through a laminate production step for producing a green sheet laminate by laminating ferrite green sheets and a firing step for firing the green sheet laminate.

The ceramic green sheet for the insulating layer 1 is mainly composed of an insulator powder composed of glass powder and filler powder, a color pigment composed of a second crystal having a spinel structure composed of oxide or sulfide of transition metal, and an organic binder. Is. The glass powder is a glass-phase glass powder as described above. In addition to the filler powder described above, the filler powder may be, for example, a composite oxide of Al ₂ O ₃ , SiO ₂ or ZrO ₂ and an alkaline earth metal oxide, depending on the electrical characteristics and mechanical characteristics of the insulating layer 1, Including ceramic powders such as composite oxides of TiO ₂ and alkaline earth metal oxides, or composite oxides containing at least one selected from Al ₂ O ₃ and SiO ₂ (for example, spinel, mullite, cordierite) May be.

The ferrite green sheet for the ferrite layer 2 is a ferrite powder that is a ferrite crystal powder as described above, or, for example, a ferrite powder prepared by pre-calcining FeFe ₂ O ₄ and CuO, ZnO or NiO, And an organic binder as a main component.

  As the organic binder contained in the ceramic green sheet for the insulating layer 1 and the ferrite green sheet for the ferrite layer 2, those conventionally used for ceramic green sheets can be used, for example, acrylic (acrylic acid, methacrylic acid) Or homopolymers or copolymers of these esters, specifically acrylic ester copolymers, methacrylic ester copolymers, acrylic ester-methacrylic ester copolymers, etc.), polyvinyl butyral , Polyvinyl alcohol-based, acrylic-styrene-based, polypropylene carbonate-based or cellulose-based homopolymers or copolymers. In view of decomposability and volatility in the firing step, an acrylic binder is more preferable.

  The ceramic green sheet for the insulating layer 1 and the ferrite green sheet for the ferrite layer 2 are prepared by preparing a slurry, applying the slurry by a coating method such as a doctor blade method, and drying the solvent in the slurry. . The slurry for producing the green sheet is 5 to 20 parts by weight of an organic binder and 15 to 50 parts by weight of an organic solvent with respect to 100 parts by weight of the insulator powder or ferrite powder, and mixed by a ball mill or other mixing means. It is prepared to have a viscosity of 3 to 100 cps by mixing. The organic solvent at this time should just be a thing which can disperse | distribute and mix | blend an insulator powder or a ferrite powder, and an organic binder favorably, and an organic solvent, water, etc. of toluene, ketones, and alcohols are mentioned. Among these, solvents having a high evaporation coefficient such as toluene, methyl ethyl ketone and isopropyl alcohol are preferable because the drying step after slurry application can be performed in a short time.

  The wiring conductor 3 is made of a metallized metal that is a sintered body of a low-resistance metal powder such as Cu, Ag, Au, Pt, Ag—Pd alloy or Ag—Pt alloy, and is a ceramic green for the insulating layer 1. A wiring conductor pattern to be the wiring conductor 3 is formed by printing a conductive paste for the wiring conductor 3 on the sheet, and is formed by simultaneous firing with the ceramic green sheet for the insulating layer 1. The wiring conductor 3 is formed on the outer surface of the glass-ceramic wiring board with a built-in coil, and an external wiring conductor for mounting an electronic component thereon or mounting on an external circuit board via a brazing material, There are internal wiring conductors for connecting the upper and lower external wirings, and the internal wiring conductors include an internal wiring layer for routing in the planar direction in the insulating layer 1 and the ferrite layer 2, and the internal wiring layers or There is a through conductor that penetrates the insulating layer 1 and the ferrite layer 2 in the thickness direction for connecting the internal wiring and the external wiring conductor.

  The method for producing the green sheet laminate is to apply heat and pressure to the ceramic green sheet for the insulating layer 1 and the ferrite green sheet for the ferrite layer 2 formed by stacking the wiring conductors 3 on the surface and inside. A method of pressure bonding, a method of applying an adhesive agent composed of an organic binder, a plasticizer, a solvent, and the like between sheets and thermocompression bonding can be employed. The conditions of heating and pressurization during lamination vary depending on the type and amount of the organic binder used, but are generally 30 to 100 ° C. and 2 to 30 MPa. The ceramic green sheets and ferrite green sheets at this time may be laminated in a necessary number depending on the thickness of the green sheets so as to have a thickness according to the characteristics required for the glass ceramic wiring board.

  The wiring conductor pattern to be the wiring conductor 3 is obtained by printing a conductive paste for the wiring conductor 3 on the surface of the ceramic green sheet for the insulating layer 1 and the ferrite green sheet for the ferrite layer 2 by a printing method such as screen printing or gravure printing. It is formed by printing a predetermined pattern. Prior to the formation of the wiring conductor pattern, the through conductor to be the wiring conductor 3 is formed with a through hole in the ceramic green sheet for the insulating layer 1 and the ferrite green sheet for the ferrite layer 2 by punching or laser processing. The hole is formed by filling the conductor paste for the wiring conductor 3 by embedding means such as printing or press filling.

  The green sheet laminate is fired by debinding at a temperature of 300 to 600 ° C. and then baking at a temperature of 800 to 1000 ° C.

  The conductor paste for the wiring conductor 3 is mixed and kneaded by kneading means such as a ball mill, a three-roll mill, a planetary mixer, etc. after adding an organic binder, an organic solvent, and a dispersant as required to the main component metal powder. It is made with.

  As the organic binder of the conductive paste, those conventionally used for the conductive paste can be used. For example, acrylic (a homopolymer or copolymer of acrylic acid, methacrylic acid or esters thereof, specifically acrylic Acid ester copolymer, methacrylate ester copolymer, acrylic ester-methacrylic ester copolymer, etc.), polyvinyl butyral, polyvinyl alcohol, acrylic-styrene, polypropylene carbonate or cellulose A homopolymer or a copolymer is mentioned. In view of decomposition and volatility in the firing step, acrylic and alkyd organic binders are more preferable.

  The organic solvent for the conductor paste is not particularly limited as long as the above-described metal powder and organic binder can be well dispersed and mixed, and terpineol, butyl carbitol acetate, phthalic acid, and the like can be used.

  The conductor paste for the wiring conductor 3 is prepared by adding 3 to 15 parts by mass of an organic binder and 10 to 30 parts by mass of an organic solvent to 100 parts by mass of the metal conductor powder, and kneading the mixture. It is desirable that the viscosity be such that a pattern having a predetermined shape can be satisfactorily formed without causing problems such as bleeding or blurring.

  The conductor paste for forming the wiring pattern to be the through conductor is adjusted to a paste having a relatively low fluidity with respect to the conductor paste for the wiring conductor 3 according to the amount of the solvent and the amount of the organic binder, and filled into the through hole. It is good to make it easy and to heat cure. Further, in order to adjust the sintering behavior, an inorganic component obtained by adding glass or ceramic powder to the metal conductor powder may be included.

  As the firing atmosphere, when the wiring conductor 3 is made of a material that is difficult to oxidize such as Ag, the firing is performed in the atmosphere. When the wiring conductor 3 is made of a material that is easily oxidized such as Cu, a nitrogen atmosphere is used so that the binder is easily removed. A humidified atmosphere is used.

  The wiring conductor 3 formed on the surface of the glass-ceramic wiring board with a built-in coil after the firing has nickel on its surface in order to strengthen the bonding with a semiconductor chip, a chip component, or an external electric circuit by soldering or the like. The layer and the gold layer may be sequentially deposited by a plating method.

  The glass-ceramic wiring board with a built-in coil according to the present invention has a coil conductor 4 formed between the ferrite layers 2 of the glass-ceramic wiring board according to the present invention having the above-described configuration, as in the examples shown in FIGS. is there. With such a configuration, the coil conductor 4 is formed on the ferrite layer 2 having a high magnetic permeability, so that the glass-ceramic wiring board with a built-in coil having a high inductance is obtained.

  The coil conductor 4 is made of a metallized metal layer that is a sintered body of metal powder, similarly to the wiring conductor 3, and the conductor paste for the coil conductor 4 is printed on the surface of the ferrite green sheet for the ferrite layer 2. Is formed between the ferrite layers 2 (incorporated in the ferrite layer 2) by laminating a ferrite green sheet for the ferrite layer 2 thereon and firing them simultaneously. In the example shown in FIG. 2 and FIG. 3, the coil conductor 4 is formed between one layer of the ferrite layer 2, but the coil conductor 4 is formed by overlapping a plurality of layers vertically between the plurality of layers of the ferrite layer 2. If a plurality of coil conductors 4 are stacked one above the other, the coil conductor pattern that becomes the coil conductor 4 and the penetration that becomes the through conductor for connecting the coil conductors to each other or between the coil conductor and the internal wiring layer A plurality of ferrite green sheets for the ferrite layer 2 on which a conductor pattern is formed may be laminated, and a ferrite green sheet for the ferrite layer 2 may be further laminated.

  As the metal powder used to manufacture the coil conductor 4, a low-resistance metal powder such as Cu, Ag, Au, Pt, Ag—Pd alloy, or Ag—Pt alloy similar to the wiring conductor 3 is used. Thereby, the electrical resistance of the coil conductor 4 can be made small.

  The glass-ceramic wiring board with a built-in coil can be manufactured by forming a coil conductor pattern between ferrite green sheets for the ferrite layer 2 in the above-described method for manufacturing a glass-ceramic wiring board. In the case of a glass-ceramic wiring board with a built-in coil as in the examples shown in FIG. 2 and FIG. 3, wiring patterns are respectively formed above and below a predetermined number of ferrite green sheets for the ferrite layer 2 including those on which coil conductor patterns are formed. A predetermined number of ceramic green sheets for the insulating layer 1 are arranged to produce a laminate, and the laminate is fired to produce a glass-ceramic wiring board with a built-in coil.

  The coil conductor pattern to be the coil conductor 4 is formed by printing a conductor paste for the coil conductor 4 on a surface of the ferrite green sheet for the ferrite layer 2 in a predetermined pattern by a printing method such as a screen printing method or a gravure printing method. The conductor paste for the coil conductor 4 may be the same as the conductor paste for the wiring conductor 3. The coil conductor pattern to be the coil conductor 4 depends on the required inductance value and size, but when formed by printing as described above, the line width and the distance between adjacent outer and inner conductors is about 0.1 mm or more. If it is, it can form easily.

  As the firing atmosphere, when the coil conductor 4 is made of a material that is difficult to oxidize such as Ag, the firing is performed in the air. When the coil conductor 4 is made of a material that is easy to oxidize such as Cu, a nitrogen atmosphere is used so A humidified atmosphere is used.

  In addition, this invention is not limited to the example of the above embodiment, A various change may be added in the range which does not deviate from the summary of this invention. For example, in the above example, a ceramic green sheet for the insulating layer 1 is arranged above and below the ferrite green sheet for the ferrite layer 2 to produce a laminate, and this laminate is fired to produce a glass ceramic wiring board. Although an example was explained, after making and firing a laminate with only a ferrite green sheet, ceramic green sheets were laminated on the top and bottom, and this laminate was fired to produce a glass ceramic wiring board. Also good.

  Examples of the glass-ceramic wiring board with a built-in coil and the manufacturing method thereof in the example of the above embodiment will be described in detail below.

First, 80% by mass of glass powder containing Si, Al, Zn and Mg as main elements as glass powder, and oxides or sulfides of transition metals as shown in the “Chemical Formula” column of “Pigment” in Table 1 as color pigments 4% by mass of the product and 16% by mass of forsterite (Mg ₂ SiO ₄ ) or garnite (ZnAl ₂ O ₄ ) powder as filler powder are mixed, and 100% by mass of the insulator powder is mixed with acrylic as an organic binder. Add 12% resin by weight, 6% by weight phthalic acid plasticizer as plasticizer and 30% by weight toluene as solvent, mix by ball mill method to prepare slurry, and use this slurry for doctor blade method Thus, a ceramic green sheet to be the insulating layer 1 having a thickness of 160 μm was formed.

  Through holes with a diameter of 150 μm for through conductors were formed in the ceramic green sheet to be the insulating layer 1 by punching with a mold. This through hole was filled with a through conductor paste by screen printing and dried at 70 ° C. for 30 minutes. As a penetrating conductor paste, 100 parts by mass of Ag powder, 10 parts by mass of glass powder as a sintering aid, 12 parts by mass of acrylic resin and 2 parts by mass of α-terpineol as an organic solvent are added, and a stirring deaerator Then, the mixture was sufficiently kneaded with three rolls after being sufficiently mixed.

  Next, a conductive paste was applied to the ceramic green sheet by a screen printing method to a thickness of 2 μm and a thickness of 20 μm, and dried at 70 ° C. for 30 minutes to form a wiring conductor pattern.

  As a conductor paste, 12 parts by mass of acrylic resin and 2 parts by mass of α-terpineol as an organic solvent are added to 100 parts by mass of Ag powder as a metal powder, and after thorough mixing with a stirring deaerator, three rolls are used. A sufficiently kneaded product was used.

Next, 700 g of FeFe ₂ O ₄ powder, 60 g of CuO powder, 60 g of NiO powder, 180 g of ZnO powder, and 4000 cm ³ of pure water were put together with zirconia balls in a pot having a capacity of 7000 cm ³ , and the ball mill was rotated by rotating the pot. After mixing over time, the dried mixed powder was placed in a zirconia crucible and heated in the atmosphere at 730 ° C. for 1 hour to produce a ferromagnetic ferrite powder. To 100 parts by mass of the ferrite powder, 10 parts by mass of butyral resin as an organic binder and 45 parts by mass of IPA as an organic solvent were added, and mixed by the same ball mill method to obtain a slurry. Using this slurry, a ferrite green sheet having a thickness of 100 μm was formed by a doctor blade method.

  Through holes with a diameter of 150 μm for through conductors were formed in this ferrite green sheet by punching with a mold. This through hole was filled with a through conductor paste by screen printing, and dried at 70 ° C. for 30 minutes to form a through conductor composition to be a through conductor. As the through conductor paste, the same one as described above was used.

  Subsequently, a conductor paste was applied to each of the eight ferrite green sheets by a screen printing method to a thickness of 30 μm and dried at 70 ° C. for 30 minutes to form a coil conductor pattern. As the conductive paste, 10 parts by mass of an acrylic resin and 1 part by mass of α-terpineol as an organic solvent were added to 100 parts by mass of Ag powder, and the mixture was sufficiently mixed by a stirring deaerator.

  Next, 8 ceramic green sheets, each of which is stacked on top and bottom of each other, are stacked so that the coil conductor pattern is positioned between the ferrite green sheets, and a pressure of 20 MPa is applied. A laminated body in which the ceramic green sheet was positioned on the surface layer was produced by thermocompression bonding at a temperature of 55 ° C.

  Next, this laminate was cut into a size of 30 × 35 mm, and then heated in air at 500 ° C. for 3 hours to remove organic components, and then in air at 900 ° C. for 1 hour. By firing, a glass-ceramic wiring board with a built-in coil in which a ferrite layer was provided between insulating layers made of glass ceramics was produced.

  Five samples each of Examples 1 to 25 and Comparative Examples 1 to 11 shown in Table 1 and Table 2 obtained as described above were prepared, and the penetration test of the fluorescent flaw detection liquid and the penetration of the red check liquid were performed. Tests, water absorption measurements, and observation with a transmission electron microscope were performed.

  In the penetration test of the fluorescent flaw detection liquid, the glass ceramic wiring board is immersed in the fluorescent flaw detection liquid, left under a pressure of 0.5 MPa for 2 hours, and then taken out from the fluorescent flaw detection liquid, and then the glass ceramic wiring with a built-in coil. The side surface of the substrate was polished, and it was confirmed whether there was penetration of the fluorescent flaw detection liquid between the insulating layer 1 and the ferrite layer 2. When there was penetration, it was determined that voids or gaps were formed at the interface between the insulating layer 1 and the ferrite layer 2.

  In the red check solution penetration test, immerse the glass ceramic wiring board in the red check solution and leave it for 10 seconds, then remove it from the red check solution, wash it with water, and then put it in the glass ceramic wiring substrate. It was confirmed whether there was any penetration. In the red check solution penetration test, it was determined that a void was formed on the glass ceramic wiring board when there was penetration.

  In measuring the water absorption rate of the glass ceramic wiring board, the glass ceramic wiring board was left in hot water at 100 ° C. for 1 hour, taken out of the hot water, and then the mass of the glass ceramic wiring board was measured. Thereafter, the glass ceramic wiring board was dried in an atmosphere of 80 ° C. for 1 hour in a drying oven, and the mass of the glass ceramic wiring board was measured. The masses after being left in warm water and after drying were compared, and the mass difference was calculated. When the mass difference was 0.1% or more, it was determined that a void was formed on the glass ceramic wiring board.

  In observation with a transmission electron microscope, first, after cutting and polishing the substrate so that the glass-ceramic wiring board with a built-in coil can be observed with a transmission electron microscope from the cross-sectional direction, the intermediate layer portion is examined with a transmission electron microscope. It was in a state where it could be observed. As the transmission electron microscope, JEM-2010F (manufactured by JEOL) was used. After observing the image and specifying the presence or absence of the intermediate layer, the crystal structure of the intermediate layer was identified by observing the diffraction grating image of the portion of the intermediate layer where the intermediate layer was present. The crystal phase was identified with a JPCDS card.

  Table 2 shows the results of the fluorescence flaw detection liquid penetration test, red check liquid penetration test, water absorption measurement, and observation with a transmission electron microscope.

  As shown in Table 2, the crystal structure of the ferrite crystal, the first crystal, and the second crystal as the color pigment are the same, and the difference in lattice constant between the first crystal and the second crystal is the lattice of the second crystal. All of the five samples of Examples 1 to 25, which are within 13.3% of the constant and the difference in lattice constant between the second crystal and the ferrite crystal is within 11.4% of the lattice constant of the second crystal, are fluorescent. It was confirmed that there was no penetration of the flaw detection liquid and the red check liquid, and the water absorption was less than 0.1%. On the other hand, all of the five samples of Comparative Examples 1 to 11 that do not satisfy even one of the conditions that are satisfied by the above-described examples have the penetration of the fluorescent flaw detection liquid and the red check liquid, and the water absorption rate. Was confirmed to be 0.1% or more. Note that the difference in lattice constant shown in Table 2 does not change continuously because it changes depending on the combination of crystals. In addition, 5/5 OK shown in Table 2 indicates that all of the five samples did not penetrate the fluorescent flaw detection liquid and the red check liquid, and 5 / 5NG indicates that all the five samples were the fluorescent flaw detection liquid and the red check liquid. Indicates that there was penetration.

  From the above results, the first crystal, the second crystal, and the ferrite crystal described in the example of the above embodiment have the same crystal structure, and the difference in lattice constant between the second crystal and the ferrite crystal is 13.3. %, And the difference in lattice constant between the second crystal and the first crystal is within 11.4% of the lattice constant of the second crystal, voids are generated at the interface between the first crystal and the second crystal. Therefore, it was confirmed that a glass-ceramic wiring board having a colored insulating layer can be obtained while maintaining the substrate strength and insulation reliability.

DESCRIPTION OF SYMBOLS 1 ... Insulating layer 2 ... Ferrite layer 3 ... Wiring conductor 4 ... Coil conductor

Claims (4)

A plurality of insulating layers comprising a glass ceramic having a glass phase and a glass including a first crystal, the insulating layer including a spinel-structured second crystal made of an oxide or sulfide of a transition metal as a color pigment, and the ferrite crystal A plurality of ferrite layers provided between the insulating layers, and wiring conductors formed on the surface and inside, wherein the first crystal, the second crystal, and the ferrite crystal have the same crystal structure , The first crystal, the second crystal, and the ferrite crystal have different lattice constants, and a difference in lattice constant between the first crystal and the second crystal is within 13.3% of the lattice constant of the second crystal. The glass ceramic wiring board is characterized in that a difference in lattice constant between the second crystal and the ferrite crystal is within 11.4% of the lattice constant of the second crystal. The first crystal is Mg ₂ SiO ₄ , the ferrite crystal is FeFe ₂ O ₄ , and the second crystal is any of FeV ₂ O ₄ , CoCr ₂ O ₄ , MnCo ₂ O _4, and CoFe ₂ O ₄ . The glass ceramic wiring board according to claim 1, wherein the number is one.   A glass-ceramic wiring board with a built-in coil, wherein a coil conductor is formed between the plurality of ferrite layers of the glass-ceramic wiring board according to claim 1. A plurality of insulating layers comprising a glass ceramic having a glass phase and a glass including a first crystal, the insulating layer including a spinel-structured second crystal made of an oxide or sulfide of a transition metal as a color pigment, and the ferrite crystal A plurality of ferrite layers provided between the insulating layers, and wiring conductors formed on the surface and inside , wherein the first crystal, the second crystal, and the ferrite crystal have the same crystal structure, The first crystal, the second crystal, and the ferrite crystal have different lattice constants, and a difference in lattice constant between the first crystal and the second crystal is within 13.3% of the lattice constant of the second crystal. together, a second crystal and method of manufacturing a glass ceramic wiring board difference in lattice constant is within 11.4% of the lattice constant of the second crystal and the ferrite crystal, forsterite 10 to 40 mass% of a filler consisting of bets, the SiO ₂ 22-52 _mass%, B 2 _{O 3} 2-12 weight%, _Al 2 _{O 3} and 9-29 wt%, the ZnO 9-29 wt% 60 to 90% by mass of glass containing 1 to 9% by mass of CaO and 7 to 21% by mass of MgO, and the molar ratio of ZnO to Al ₂ O ₃ is 0.8 to 1.2, FeV ₂ O ₄ , A first preparation step of preparing a plurality of ceramic green sheets having 2 to 8% by mass of the color pigment composed of any one of CoCr ₂ O ₄ , MnCo ₂ O ₄ and CoFe ₂ O ₄ ;
A second preparation step of preparing a ferrite green sheet having FeFe ₂ O ₄ ;
The ceramic green sheet and the ferrite green sheet are laminated to form a green sheet laminate by forming a conductor pattern to be a wiring conductor between layers and laminating,
A method for producing a glass ceramic wiring board, comprising: a firing step of firing the green sheet laminate.

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